亚热带常绿阔叶林几种乔木种子萌发特性研究

A COMPARATIVE STUDY ON SEED GERMINATION CHARACTERISTICS OF SEVERAL TREE SOECIES IN SUBTROPICAL EVERGREEN BROAD-LEAF FORESTS

在实验室条件下,对3种模拟光环境中亚热带常绿阔叶林乔木树种罗浮柿(D iospyros m orrisiana)、香樟(C inna-m omum camphora)、白毛新木姜子(Neolitsea aurata)的种子萌发特性进行了研究,并与同一地区的典型阳性行道树种复羽叶栾树(Koelreupena bipinnata)进行了对比。阳生树种复羽叶栾树在各光环境中总萌发率均超过90%,萌发格局表现为前期快,后期平缓;罗浮柿和白毛新木姜子萌发率随着光照水平减弱而升高,白毛新木姜子仅在黑暗中萌发率可达59%,萌发格局表现为整个萌发过程平缓。香樟种子萌发率低,可能与未解除休眠有关。以上结果表明,3种常绿阔叶林乔木和阳性树种复羽叶栾树的种子萌发对光照环境的响应有着显著的差异,这种差异可能与物种的耐阴性、物种原有生境的稳定性和种子的大小有紧密关系。

An experiment was made under lahoratory conditions to study the germination of three subtropical evergreen broad - leaf tree species , Diospyos morrisiana , Cinnamomunt camphora and Neolitsea aurata, in 3 simulated light environments, and the 3 species were compared with the heliophyte street tree species Koelreupena bipinnata. Total germination rate of K. bipinnata exceeded 90% in all the simulatred light conditions. Its seeds germinated rapidly in the earty stages and slowed down in the later stages. The germination rate of D. morrisiana seeds was considerably higher in understory and dark than that＇in the forest gap. The germination rate of N. aurata in the dark was 59% and the germination pattern of the last 2 species remained slow throughout the study period. The germination of C. camphora was poor, a phenomenon that might be related to the fact that the seed failed to break dormancy in the period of incubation. Therefore, significant differences existed between the. three tree species studied and K. bipinata and among the three species themselves in their response to the light conditions. These differences may be associated with the shade tolerance of the species, their stability to their original habitats and the size of their seeds.